Electron cyclotron resonance plasma assisted pulsed laser deposition for compound host film synthesis and in situ doping

Abstract

We developed a method for compound host film synthesis and in situ doping based on plasma assisted pulsed laser deposition by coablation of two targets with two pulsed laser beams. The feasibility of this method was demonstrated by the preparation of Er-doped GaN films. In the reactive nitrogen environment and with the assistance of nitrogen plasma generated from electron cyclotron resonance microwave discharge, the ablation of a polycrystalline GaAs target resulted in the reactive deposition of a GaN host film, whereas the ablation of a metallic Er target provided the host with Er atoms for in situ doping in the growing GaN host film. Hexagonal GaN films were formed on a silicon substrate as the host and Er was incorporated into the host with controlled concentration. We found that the composition of the compound host could be adjusted by varying the laser fluence on the target for host deposition or the energy of the plasma stream bombarding the growing host film. The dopant concentration could also be independently controlled to vary in a wide range by changing the pulse repetition ratio of the two laser beams or the laser fluence on the target for dopant supply. It was also proved that doping of very low concentrations could be easily realized by simply adjusting the pulse repetition rate and the fluence of the second laser.

Formation of diatomic molecular radicals in reactive nitrogen-carbon plasma generated by electron cyclotron resonance discharge and pulsed laser ablation

“…Such a plasma offers several merits in plasma processing for materials synthesis and fabrication. 11,12 For the purposes of this paper, we have focused our attention on the formation of diatomic molecular radicals C 2 and CN in a hybrid nitrogen-carbon plasma resulted during the expansion of the carbon plume induced by ablating a graphite target in the nitrogen plasma generated by ECR discharge of N 2 gas. C 2 and CN species are particularly important for the synthesis of various carbon nanostructures, such as fullerenes, carbon nanotubes, and carbon nitride nanocones, and can act as building units for such nanomaterials.…”